WO2007007593A1

WO2007007593A1 - Handover control apparatus, mobile communication system, and handover method

Info

Publication number: WO2007007593A1
Application number: PCT/JP2006/313323
Authority: WO
Inventors: Yasuhiro Kato; Hideaki Takahashi; Wuri Andarmawanti Hapsari; Takehiro Nakamura
Original assignee: Ntt Docomo, Inc.
Priority date: 2005-07-08
Filing date: 2006-07-04
Publication date: 2007-01-18
Also published as: CN101218836B; KR20080026187A; JP2007019982A; JP4711760B2; CN101218836A; US8478274B2; US20090305704A1; EP1903810A1; TW200711503A; EP1903810A4

Abstract

A handover control apparatus comprises a service determining means that determines the type of a service during communication of a mobile station; and a handover processing means that performs, based on a determination result, a handover by use of the procedure of one of a network-led handover and a mobile station-led handover. It may be arranged that a handover be performed by use of the procedure of the network-led handover when a service during communication of a mobile station includes a communication quality assurance type of service.

Description

Specification

Technical field of handover control apparatus, mobile communication system, and handover method

TECHNICAL FIELD [0001] The present invention relates to a handover control apparatus, a mobile communication system, and a handover method in a mobile communication system that provides a plurality of different services of a communication quality assurance service and a non-guarantement service.

Background art

[0002] As the handover technology, there are network-driven handono and mobile station-driven handover widely adopted in cellular systems such as PDC and IMT-2000.

[0003] Network-driven handover is a method in which a mobile station measures the reception level and reception quality of neighboring cells and reports information about cells that can be candidates for switching to the network using a control signal. Based on huntover.

[0004] The network side that has received the control signal determines information on the network side, such as the radio resource usage status of the candidate cell, and determines the switching destination cell. In addition, the network side issues a switch preparation instruction to the base station that accommodates the switching destination cell, and then notifies the mobile station of the switching destination cell and performs node handover processing. This handover is generally used for cell switching of communication channels that require the maintenance of communication quality.

[0005] As a feature of this network-driven handover method, the mobile station selects a switching destination candidate. The final switching destination is determined by the network, cell switching on the mobile station side, and network switching on the network side. Transfer route switching can be performed at the same timing. Thereby, reliable and high-speed handover can be realized for the optimum cell.

[0006] However, the network-driven handover method has the disadvantages that there are many control procedures and many extra control states such as a signal waiting state. In particular, the processing when the mobile station cannot successfully hand over to the designated switching destination cell is complicated. Regardless of whether the mobile station has successfully captured the handover destination radio wave, the network side performs user data path switching processing. The state becomes inconsistent, and a process for canceling these processes is required.

[0007] Here, if an appropriate area design is performed, the probability that the node fails to fail can be reduced. However, it is necessary to consider because handover failures occur at a certain rate due to factors that are difficult to avoid, such as an instantaneous out of service area or due to a tunnel.

[0008] On the other hand, in mobile station initiated handover, a mobile station autonomously determines a switching destination cell from the reception levels and reception qualities of a plurality of neighboring cells, and executes a node handover at an arbitrary timing of the mobile station. Is.

[0009] In mobile station initiated handover, control is performed to notify the network side of the switching destination cell in advance for the purpose of shortening the radio synchronization time, and to receive notification regarding the channel information of the network side power switching destination cell. It is possible to combine procedures. However, unlike network-driven handover, the network side does not require control procedures such as securing radio resources for the switching destination channel and setting switching timing.

[0010] Mobile station initiated handover is mainly used in cell switching in a communication state on a common channel and reconnection operation when network initiated handover fails.

[0011] A feature of the mobile station initiated handover is that the mobile station performs cell switching autonomously and the network changes the transfer path after cell switching, so that control can be simplified overall. . Even if the mobile station side cannot properly capture the radio waves from the cell that was initially determined, the network side control will be performed when the retry is successful in any cell that does not affect the network side operation. If you start, there are advantages

[0012] However, since the mobile station autonomously transitions, it is impossible to make a node over in consideration of information on the network side such as the usage status of radio resources. It is particularly suitable for voice and videophone services that require a certain level of communication quality and wireless resources. In addition, since the user data path is switched after confirming the completion of the handover with the control signal, the transmission delay temporarily increases.

Disclosure of the invention

Problems to be solved by the invention

However, the background art described above has the following problems. [0014] When network-driven handover is applied to a communication channel, there is a problem that the processing becomes complicated when there are many processing procedures, especially when the radio waves cannot be normally captured in the switching destination cell.

[0015] On the other hand, when mobile station initiated handover is uniformly applied to a communication channel, control is simple, but there is a problem that an event in which quality cannot be satisfied due to insufficient radio resources occurs. There is also a problem that the delay at the time of handover is larger than that of network-driven handover.

Therefore, an object of the present invention is to provide a handover control apparatus, a mobile communication system, and a handover method that can reduce the control load while maintaining the communication quality required by each service in the handover.

Means for solving the problem

[0017] In order to solve the above problems, a handover control apparatus of the present invention is a handover control apparatus in a mobile communication system that provides a mixture of a plurality of different services of a communication quality guarantee type and a non-guarantement type. Service determining means for determining a service in which the station is communicating, and handover processing means for performing handover according to one of a network-driven handover and a mobile station-driven handover based on the determination result. One of the features.

With this configuration, network-driven handover and mobile station-driven handover can be used and separated according to the service being communicated.

[0019] The mobile communication system of the present invention is a mobile communication system that includes a mobile station and a radio base station, and provides a plurality of different services of different communication quality assurance types and non-guarantement types. The mobile station includes communication quality measuring means for measuring communication quality of neighboring cells, handover determining means for determining whether or not to perform handover based on the communication quality, and based on the determination result, Mobile station side handover processing means for performing a handover process, wherein the radio base station is a service determination means for determining a service that the mobile station is communicating with, and a network-driven handover and transfer based on the determination result. One of the features is that it includes a base station-side handover processing means for performing handover by one of the procedures initiated by the mobile station. With this configuration, it is possible to reduce the control load while maintaining the communication quality required by each service.

[0021] The handover method of the present invention is a handover method in a mobile communication system that includes a mobile station and a radio base station, and provides a plurality of different services of different communication quality assurance types and non-guarantement types. Then, a service determination step for determining a service that the mobile station is communicating with, and a handover that performs handover according to one of a network-driven handover and a mobile station-driven handover based on the determination result. One of the features is that it includes a server processing step.

[0022] By doing in this way, it is possible to use and separate network-driven handono and mobile station-driven handover according to the service being communicated.

The invention's effect

[0023] According to the embodiment of the present invention, it is possible to realize a handover control device, a mobile communication system, and a handover method that can reduce the control load while maintaining the communication quality required by each service in the handover. Brief Description of Drawings

FIG. 1 is an explanatory diagram showing a mobile communication system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a handover control apparatus according to an embodiment of the present invention.

FIG. 3 is a block diagram showing a mobile station that works in one embodiment of the present invention.

FIG. 4 is an explanatory diagram showing network-driven handover that works in one embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a mobile station initiated handover which is related to one embodiment of the present invention.

FIG. 6 is a flowchart showing the operation of the handover control apparatus according to one embodiment of the present invention.

FIG. 7 is a flowchart showing the operation of the mobile station according to one embodiment of the present invention.

Explanation of symbols

[0025] 100, 100, 100, 100, 100 Wireless communication device

1 2 3 4

200 mobile stations

300 300, 300 exchange ^ ¾ 400 core network

500 Handover control device

BEST MODE FOR CARRYING OUT THE INVENTION

Next, embodiments of the present invention will be described with reference to the drawings.

In all the drawings for explaining the embodiments, the same reference numerals are used for those having the same function, and repeated explanation is omitted.

A mobile communication system according to an embodiment of the present invention will be described with reference to FIG.

[0028] The mobile communication system according to the present embodiment provides a mixture of a plurality of services having different communication quality assurance services and non-guarantement services. Communication quality assurance service is a service that guarantees a certain transmission speed and transmission delay time, as typified by voice service. A non-guaranteed service is a service that does not guarantee transmission speed and transmission delay time as typified by Web services. The mobile communication system is connected to one or more intersections 300 (300, 300) connected to the core network 400 and to the intersection 300.

1 2

One or more radio base stations 100 (100, 100, 100, 100) and radio base station 100

1 2 3 4

1 or a plurality of mobile stations 200 capable of wireless communication.

[0029] For example, as shown in Fig. 1, radio base stations 100 and 100 are connected to an exchange 300.

1 2 1

Radio base stations 100 and 100 are connected to AC 300.

3 4 2

[0030] The wireless base station 100 (100, 100, 100, 100) is connected between wired and wireless in each layer.

1 2 3 4

A protocol conversion unit that performs protocol conversion and a radio network controller as a handover control apparatus that performs radio control, which will be described later, are provided. The radio control device performs control such as establishment and maintenance of a radio link with the mobile station and a node over.

[0031] The mobile station 200 terminates all layers from the physical layer to the application layer. The mobile station 200 includes a radio control unit. The radio control unit performs control such as establishment and maintenance of a radio link with the radio base station and maintenance.

[0032] The exchange shelf 300 sets a transfer path and transfers data. The exchange shelf 300 switches the transfer path in accordance with an instruction from the radio base station 100 in the handover. The exchange 300 can be configured by, for example, an ATM exchange, an IP exchange, etc., regardless of the data exchange method. [0033] Core network 400 includes a home 'location' register (HLR: home location register) and the like for holding exchanges connected to other networks, subscriber information, and the like.

[0034] In this embodiment, a case will be described in which a radio control device as a handover control device is arranged in a radio base station. However, when a radio control station is separately defined and a radio control device is arranged in the radio control station, However, the following explanation is equivalent.

Next, a radio control apparatus 500 provided in the radio base station 100 according to the present embodiment will be described with reference to FIG.

Radio control apparatus 500 has all the radio control functions necessary for communication with mobile station 200.

Radio control apparatus 500 includes control unit 502, service management unit 504 serving as a service determination unit connected to control unit 502, and handover processing as a base station side handover processing unit and a node processing unit. Part 506.

[0038] The service management unit 504 manages a service during communication for each user, and manages whether the service is a quality assurance type or a quality non-guarantement type for each service. For example, the service management unit 504 determines a service that the mobile station 200 is communicating with when the mobile station 200 notifies the candidate of the switching destination cell determined based on the quality measurement of the neighboring cells. . Specifically, the service management unit 504 determines whether or not the service with which the mobile station 200 is communicating includes a communication quality assurance type service. Communication quality assurance services include voice and videophone.

[0039] The handover processing unit 506 performs a handover process. The handover processing unit 506 has two types of procedures of network initiative type and mobile station initiative type as hand-on functions during communication. The network-driven handover process is a handover process in which the network side determines the node handover destination and prepares in advance such as setting the mobile station information in advance to the node base station. The mobile station initiated handover process is a handover process in which the mobile station autonomously determines the handover destination base station and resets the mobile station information after the node is over and switches the route. For example, the handover processing unit 506 determines that the service that the mobile station 200 is communicating with includes a communication quality assurance type service based on the determination result in the service management unit 504. If it is determined that a handover is not included, a mobile station initiated handover is performed.

[0040] Here, as described above, the network-driven handover is a handover in which a switching destination cell and switching timing are determined on the network side, and radio channel setting and path switching setting are performed in advance. is there. In addition, as described above, the mobile station initiative type handover is a handover in which a switching destination cell and switching timing are determined on the mobile station side, and path switching is set after the mobile station autonomously switches the cell. It is.

The control unit 502 controls the service management unit 504 and the node over processing unit 506.

[0042] Next, the mobile station 200 that works in the embodiment will be described with reference to FIG.

[0043] The mobile station 200 according to the present embodiment includes the radio control unit 201 as described above, and the radio control unit 201 is connected to the communication quality measurement unit 202 and the communication quality measurement unit 202. A determination unit 204 and a handover processing unit 206 as a mobile station side handover processing means connected to the handover determination unit 204 are provided.

The communication quality measuring unit 202 measures the communication quality of neighboring cells, for example, the reception level and the reception quality, and inputs the measurement result to the node over determination unit 204.

[0045] The handover determining unit 204 determines whether or not to perform handover based on the measurement result. For example, the handover determining unit 204 determines whether or not to perform a handover based on a preset node over condition, and inputs the result to the node over processing unit 206.

[0046] The handover processing unit 206 performs a handover process. For example, the handover processing unit 206 performs cell switching and establishment of a radio link.

[0047] Next, handover in the mobile communication system according to the present embodiment will be described with reference to FIG. 4 and FIG.

[0048] First, a network-driven handover in a mobile communication system that works according to the present embodiment will be described with reference to FIG. In the present embodiment, a case where the mobile station 200 performs a handover (HO) to the radio base station 100 100 will be described.

1 2

[0049] The communication quality measurement unit 202 of the mobile station 200 receives neighboring cells according to a predetermined procedure. At least one of the level and the reception quality is measured, and the measurement result is input to the node determination unit 204. The handover determining unit 204 determines whether or not the measurement result satisfies the handover condition, and inputs the result to the node over processing unit 206.

[0050] When information indicating that the handover condition is satisfied is input (1), the handover processing unit 206 determines at least one candidate cell as a handover destination candidate, and information indicating the determined candidate cell Is notified to the network side by a control signal, for example (2).

[0051] Receiving the notification of the information indicating the candidate cell, the radio base station 100 determines, in the service management unit 504, the service that the mobile station 200 that has transmitted the information indicating the candidate cell is communicating with. For example, the service management unit 504 of the radio base station 100 determines whether or not the service with which the mobile station 200 is communicating includes a communication quality assurance type service. The result is input to the handover processing unit 506 via the control unit 502.

[0052] Based on the determination result in the service management unit 504, the handover processing unit 506 determines, for example, the degree of congestion of candidate cells when it is determined that the service being communicated with by the mobile station 200 includes a communication quality assurance type service. Based on the above, a switching destination cell is determined by a predetermined procedure (3), and a channel setting instruction is given to the switching destination radio base station 100. Han

2

The passover processing unit 506 issues a transfer path switching instruction to the joint unit 300 (4).

[0053] Next, the handover processing unit 506 of the radio base station 100 confirms the preparation on the network side, notifies the mobile station 200 of the information of the switching destination cell, and instructs the switching timing (5).

[0054] The handover processing unit 206 of the mobile station 200 performs cell switching (6). The hand-over processing unit 206 of the mobile station 200 confirms the establishment of the radio link and then hands over to the base station 100 that is the switching destination.

2 Send a handover notification (7).

[0055] The handover processing unit 506 of the switching destination base station 100

2

A channel release instruction is sent to (8), and handover completion is transmitted to the mobile station 200 (9).

[0056] With the above procedure, all handover procedures are completed.

[0057] The characteristics of this network initiated handover will be described.

[0058] In addition to the reception quality information from mobile station 200, a switching destination cell is determined based on information obtained only on the network side, such as the degree of congestion. As a result, the degree of congestion is high. It is possible to allocate cells while avoiding loosely congested cells, and it is possible to reliably continue the service in the switching destination cell.

[0059] In addition, switching timing can be set on the network side, transfer switching on the exchange side and cell switching on the mobile station can be performed almost simultaneously, and hand-over with less signal loss and delay is possible.

[0060] Next, mobile station initiated handover in the mobile communication system according to the present embodiment will be described with reference to FIG.

[0061] The communication quality measuring unit 202 of the mobile station 200 performs measurement of at least one of the reception level and the reception quality of the neighboring cells according to a predetermined procedure, and the measurement result is determined as a node determination unit 204. To enter. The handover determining unit 204 determines whether or not the measurement result satisfies the handover condition, and inputs the result to the node over processing unit 206.

[0062] When information indicating that the handover condition is satisfied is input (1), the handover processing unit 206 determines at least one candidate cell as a handover destination candidate, and information indicating the determined candidate cell Is notified to the network side by a control signal, for example (2). Up to this point, it is basically the same as network-driven handover.

[0063] Next, the radio base station 100 notifies channel information regarding the candidate cell to be switched to the mobile station 200 that has notified the information indicating the candidate cell (3).

[0064] According to the procedures (1) to (3), when the handover processing unit 206 of the mobile station 200 performs cell switching, the procedure for receiving broadcast information of the switching destination cell is reduced, and the cell switching time is reduced. It can be shortened.

[0065] Next, the handover processing unit 206 of the mobile station 200 autonomously determines a switching destination cell based on channel information regarding the switching destination candidate cell, and performs cell switching at an arbitrary timing (4). .

[0066] After confirming that the radio link has been established, the handover processing unit 206 determines that the switching destination base station 100

2 Send handover notification (5).

[0067] The handover processing unit 506 of the radio base station 100 switches the transfer route to the exchange 300.

2

And a channel release instruction to the switching source base station 100 (6), and a handover completion is transmitted to the mobile station 200 (7). [0068] The handover procedure is completed by the above procedure.

[0069] Here, in the mobile station initiated handover, the procedures (1) to (3) are not essential and should be omitted.

[0070] The features of this mobile station initiated handover will be described.

[0071] The mobile station 200 autonomously determines the switching timing and the switching destination cell, and the transfer path is switched after the cell switching.

[0072] Compared to network-initiated handover in which a candidate cell for switching destination is determined in advance and a route switching instruction is issued, the control state is particularly small. There is an advantage in that the switch back control for canceling the switching is not necessary when the node over fails, and the load of the control processing is light.

[0073] On the other hand, there is a problem that the information held on the network side cannot be considered! /, And there is a problem that the data transmission delay increases when handover is performed. This hand-over method is sufficient for best F packet service that does not require guarantees.

[0074] Next, the operation of the radio network controller 500 according to the present embodiment will be described with reference to FIG.

[0075] A candidate cell notification signal is received from mobile station 200 (step S602).

[0076] Next, service management section 504 determines whether or not the quality assurance type is included in the service communicated by corresponding mobile station 200 that has transmitted the candidate cell notification signal (step S60).

Four).

[0077] If the service with which the mobile station is communicating includes a quality assurance service (step S604: YES), it is determined that network (NW) -driven handover is to be performed, and network-driven such as determining the destination cell A type handover procedure is executed (step S606). For example, the handover processing unit 506 notifies the mobile station 200 of information indicating the switching destination cell determined on the network side, transmission timing, and the like.

[0078] On the other hand, if the service with which the corresponding mobile station 200 is communicating does not include the quality assurance type (step S604: NO), the mobile station 200 only notifies the channel information of the switching destination cell candidate ( Step S608). [0079] After that, when the mobile station 200 autonomously performs handover, the mobile station initiated handover procedure is executed.

[0080] Next, the operation of the mobile station 200 that works according to the present embodiment will be described with reference to FIG. Here, the operation of the mobile station 200 in the mobile station initiated handover will be described.

[0081] The communication quality measuring unit 202 measures the communication quality of neighboring cells, for example, the reception level and the reception quality (step S702).

Next, handover determining section 202 determines whether or not the communication quality satisfies the handover condition based on the measurement result (step S 704).

If it is determined that the handover condition is satisfied (step S 704: YES), the handover processing unit 206 determines a handover destination candidate cell and notifies the radio base station (step S 706). On the other hand, if it is determined that the handover condition is not satisfied (step S7

04: NO), return to step S702.

Next, the handover processing unit 206 autonomously determines a switching destination cell, and performs cell switching at an arbitrary timing (step S708). In this case, the handover processing unit 206

Alternatively, the switching destination cell may be determined autonomously based on the channel information regarding the switching destination candidate cell notified of the radio base station power.

[0085] Next, the handover processing unit 206 transmits a handover notification to the switching destination base station (step S708).

[0086] In the case of network initiated handover, the mobile station 200 performs the operations of step S702 and step S706, and then performs cell switching according to the notified switching destination cell information and the switching timing. Do. Thereafter, the mobile station 200 transmits a handover notification to the switching destination base station.

[0087] According to the embodiment of the present invention, the handover procedure is selectively used according to the required quality of the service during communication. In this way, when quality assurance type such as voice is included, the optimal switching destination can be selected by network-driven type, and data loss and delay due to transfer path switching can be minimized. . In addition, for non-guaranteed quality services such as best F packet service, delay fluctuations can be tolerated to some extent, so it is possible to reduce the control load by performing mobile station initiated handover. But Therefore, the quality aspect and the control load aspect can be optimized by the handover method used in this embodiment.

Industrial applicability

[0088] The handover control device, the mobile communication system, and the handover method that are useful in the present invention can be applied to a mobile communication system.

[0089] This international application claims priority based on Japanese Patent Application No. 2005-200550 filed on July 8, 2005. The entire contents of 2005-200550 are incorporated herein by reference. Incorporate.

Claims

The scope of the claims

[1] A handover control apparatus in a mobile communication system that provides a mixture of different services of a communication quality assurance type service and a non-guaranteed type service:

Service determination means for determining the type of service with which the mobile station is communicating;

A handover control device comprising: a handover processing unit that performs a handover by one of a network initiated handover and a mobile station initiated handover based on the determination result.

[2] In the handover control device according to claim 1,!

The service determination means determines whether or not the service that the mobile station is communicating with includes a communication quality assurance service,

The handover control apparatus according to claim 1, wherein the handover processing means performs handover according to a network-initiated handover procedure when a service that the mobile station is communicating with includes a communication quality assurance type service.

[3] A mobile communication system that includes a mobile station and a radio base station and provides a mixture of a plurality of different services of a communication quality assurance type service and a non-guaranteed type service:

The mobile station

Communication quality measuring means for measuring the communication quality of neighboring cells;

Handover determining means for determining whether or not to perform handover based on the communication quality;

A mobile station-side handover processing means for performing a handover process based on the determination result;

With

The radio base station is

Service determination means for determining the type of service that the mobile station is communicating based on the determination result;

Based on the determination result, the base station-side handover that performs handover by one of the network-driven handover and the mobile station-driven handover Processing means;

A mobile communication system comprising:

[4] In the mobile communication system according to claim 3,

The mobile communication system according to claim 1, wherein the base station side handover processing means performs a handover by a network initiated handover procedure when a service being communicated by the mobile station includes a communication quality guaranteed service.

[5] In the mobile communication system according to claim 4,

The mobile communication system, wherein the base station side handover processing means determines a cell to which a mobile station is switched, and switches a transfer path at the same timing as the cell switching of the mobile station.

[6] In the mobile communication system according to claim 4,

The mobile communication system according to claim 1, wherein the base station-side handover processing means performs handover by a mobile station initiated handover procedure when the service being communicated by the mobile station is a communication quality non-guaranteed service.

[7] In the mobile communication system according to claim 6,

The mobile communication system according to claim 1, wherein the base station-side handover processing means changes a transfer route after cell switching by the mobile station.

[8] A handover method in a mobile communication system that includes a mobile station and a radio base station and provides a mixture of a plurality of different services of a communication quality guarantee type service and a non-guarantement type service:

A service determination step of determining a type of service being communicated by the mobile station; a handover processing step of performing handover according to one of a network-driven handover and a mobile station-driven handover based on the determination result; Up;

A handover method comprising:

[9] In the handover method according to claim 8, Said service determining step is a step of determining whether or not the service that the mobile station is communicating with includes a communication quality assurance type service;

Have

The handover processing step is a step of performing handover according to a network-driven handover procedure when a service in communication with a mobile station includes a communication quality assurance type service;

A handover method characterized by comprising:

In the mobile communication system according to claim 9,

The handover processing step is a step of performing a handover by a mobile station initiated handover procedure when a service that the mobile station is communicating with is a communication quality non-guaranteed service;

A handover method characterized by comprising: